lncRNA RMST suppresses the progression of colorectal cancer by competitively binding to miR-27a-3p/RXRα axis and inactivating Wnt signaling pathway.

Colorectal cancer (CRC) ranks the 3rd in cancer types globally. Long noncoding RNAs (lncRNAs) are related to the initiation and progression of CRC. The current study plans to reveal the action of rhabdomyosarcoma 2-associated transcript (RMST) in CRC. The results show that RMST is downregulated in CRC specimens and cell lines relative to normal specimens and a fetal normal colon cell line (FHC), respectively. Elevation of RMST represses cell proliferation and colony formation and induces cell apoptosis in CRC cells. Bioinformatic analysis reveals a binding site in RMST for miR-27a-3p. The direct association between RMST and miR-27a-3p is confirmed by dual luciferase reporter assay, RNA pull-down assay, and real time-quantitative polymerase chain reaction (RT-qPCR). miR-27a-3p is upregulated in CRC tumor specimens relative to normal specimens, and there is a negative correlation between RMST and miR-27a-3p in CRC tumor specimens. In addition, the effects of RMST overexpression are weakened by the elevation of miR-27a-3p. RMST and retinoid X receptor (RXRα) share the same complementary site with miR-27a-3p. The direct association between RXRα and miR-27a-3p is confirmed by RNA pull-down assay, RT-qPCR and western blot analysis. Overexpression of RMST induces RXRα expression and inactivates the Wnt signaling pathway by decreasing ß-catenin levels in CRC cells. Collectively, our findings reveal a pivotal role of RMST in regulating miR-27a-3p/RXRα axis and counteracting Wnt signaling pathway during the progression of CRC.

NLRP3 ablation enhances tolerance in heat stroke pathology by inhibiting IL-1ß-mediated neuroinflammation.

BACKGROUND: Patients with prior illness are more vulnerable to heat stroke-induced injury, but the underlying mechanism is unknown. Recent studies suggested that NLRP3 inflammasome played an important role in the pathophysiology of heat stroke. METHODS: In this study, we used a classic animal heat stroke model. Prior infection was mimicked by using lipopolysaccharide (LPS) or lipoteichoic acid (LTA) injection before heat stroke (LPS/LTA 1 mg/kg). Mice survival analysis curve and core temperature (TC) elevation curve were produced. NLRP3 inflammasome activation was measured by using real-time PCR and Western blot. Mice hypothalamus was dissected and neuroinflammation level was measured. To further demonstrate the role of NLRP3 inflammasome, Nlrp3 knockout mice were used. In addition, IL-1ß neutralizing antibody was injected to test potential therapeutic effect on heat stroke. RESULTS: Prior infection simulated by LPS/LTA injection resulted in latent inflammation status presented by high levels of cytokines in peripheral serum. However, LPS/LTA failed to cause any change in animal survival rate or body temperature. In the absence of LPS/LTA, heat treatment induced heat stroke and animal death without significant systemic or neuroinflammation. Despite a decreased level of IL-1ß in hypothalamus, Nlrp3 knockout mice demonstrated no survival advantage under mere heat exposure. In animals with prior infection, their heat tolerance was severely impaired and NLRP3 inflammasome induced neuroinflammation was detected. The use of Nlrp3 knockout mice enhanced heat tolerance and alleviated heat stroke-induced death by reducing mice hypothalamus IL-1ß production with prior infection condition. Furthermore, IL-1ß neutralizing antibody injection significantly extended endotoxemic mice survival under heat stroke. CONCLUSIONS: Based on the above results, NLRP3/IL-1ß induced neuroinflammation might be an important mechanistic factor in heat stroke pathology, especially with prior infection. IL-1ß may serve as a biomarker for heat stroke severity and potential therapeutic method.

Laser speckle contrast imaging and Oxygen to See for assessing microcirculatory liver blood flow changes following different volumes of hepatectomy.

OBJECTIVE: Portal hyperperfusion after extended hepatectomy or small-for-size liver transplantation may induce organ dysfunction and failure. This study was designed to monitor and characterize the hepatic microcirculatory perfusion following different volumes of hepatectomy in rats by using laser speckle contrast image (LSCI) and Oxygen to See (O2C), a spectrometric device. METHODS: The microcirculatory liver blood flow of the rats that underwent 68%, 85% and 90% hepatectomy (68PH, 85PH and 90PH) was monitored with LSCI and O2C before and following the hepatectomy. The portal venous flow (PVF) and hepatic arterial flow (HAF) were measured with an ultrasonic flowmeter. Liver regeneration, liver injury, histologic evaluation and gene expression were also assessed at 12h, 24h, 3d and 7d post hepatectomy. RESULTS: All the 68PH and 85PH rats survived, and 57% of the 90PH rats survived. After hepatectomy, both PVF and HAF decreased transiently, with the PVF of the 85PH and 90PH rats significantly lower than that of the 68PH rats. In contrast, the PVF and HAF per gram of liver weight were greatly increased after liver resection and were proportional to the volume of resected liver. Correspondingly, the microcirculatory liver blood flow of the 68PH, 85PH and 90PH rats, as assessed by both LSCI and O2C, were increased after hepatectomy, and the 90PH group was significantly higher than the 68PH and 85PH groups. The hyperperfusion continued for approximately 3days and returned to baseline following the completion of liver regeneration. The liver venous oxygen saturation of the three groups decreased immediately after hepatectomy and returned to baseline from 24h after hepatectomy. The 90PH rats also showed delayed liver regeneration and the most severe liver injury, as reflected by increased serum ALT, AST and TBIL levels, hepatocellular vacuolization, and inflammatory and endothelial constriction gene expressions (TNF-α, IL-1ß, MIP-1α, ET-1 and TM-1). CONCLUSION: Hepatic microcirculation hyperperfusion resulting from major and extended liver resection could be assessed by LSCI and O2C methods. The 90PH in rats led to extraordinary sinusoidal hyperperfusion, severe endothelial injury and liver failure. Monitoring the changes of hepatic microcirculation perfusion following extended hepatectomy or small-for-size liver transplantation may help to analyze the extent of hyperperfusion.